A iPhone 4 isn't cheap – the handsets will set you back at least $199 with a contract – but by selling your old iPhone, you can defray part of the cost. Plenty of services will pay cash for iPhones in good condition. Options abound. Looking for a place to start? Check Gazelle.com, which offers $96 for a 16GB iPhone 3G, or the oh-so-subtly-named CashForiPhones.com.

Option B: Donate your old iPhone

If you're not pressed for cash, you might consider donating your old iPhone to a nonprofit organization. CellPhonesForSoldiers.com, for instance, is currently accepting smartphone donations, and the site offers a free shipping label, to make the process easier. Another possibility: Call To Protect says it has raised more than $3.5 million from refurbished phone sales. The earnings go toward grants for smaller groups fighting domestic violence.